Combination hydrocarbon dehydrogenation and hydrogenation process



` A. s. RAMAGE Oct..V l

COMBINATION HYDROCARBON DEHYDROGENATION AND HYDROGENATION PROCESS FiledAug. 25, 1944 FFSS En 0:0

Y( NEW 4.25.0 NLR- INVEOR. A/exa/zaer 5. @maja i BY I Patented Oct. 15,1946 COMBINATION HYDROCARBON DEI-IYDRO- GENATION AND HYDROGENATION PROC-ESS Alexander S. Ramage, Detroit, Mich., assignor to Albert A. F.Maxwell, Detroit, Mich., as trustee Application August 25, Serial No.551,265

9 Claims. 1

The present invention relates to a novel process for the treatment ofhydrocarbons, such, for example, as hydrocarbons contained in crudeoils, low temperature tar oils, shale oils, and the like, for thepurpose of producing a gas rich in ethylene and containing only smallamounts of propylene and butylene, and a high yield of a liquid mixtureconsisting chiefly of liquid aromatics and the condensation products ofthe aromatics and gaseous olens of high octane number.

The present application is a continuation-inpart of my copendingapplication Serial No. 475,468, entitled Treatment of hydrocarbon oils,filed February 11, 1943.

In my prior Patent No. 1,752,692, issued April 1, 1930, and entitledProcess for the production of gas and aromatic hydrocarbons from heavyhydrocarbon oils, I have disclosed a process and apparatus in which thehydrocarbons were dehydrogenated in the lower tubes of the converter bycontact with ferrie oxide as the reactive agent. The dehydrogenatedgases and vapors with a large volume of steam were subsequently passedthrough the upper tubes in the converter which were filled with metalliciron.

While the results of this process were quite satisfactory as a gasprocess, the liquid condensate tested 70 to 75 octane only.

This invention contemplates a process which Will give considerablyhigher yields of ethylene as Well as liquid condensate having a muchhigher octane number.

The hydrocarbons which are to be transformed comprise mainly paraflins(CnI-Izn+2) and olens (CHI-Ian). These hydrocarbons are rstdehydrogenated in the presence of heat to form aromatic hydrocarbons andunsaturated aliphatic hydrocarbons. During dehydrogenation the olefnsalso broke down into hydrocarbons having a lesser number of carbonatoms. After being subjected to the dehydrogenating step, thehydrocarbons are next subjected to a hydrogenating step in the presenceof heat in which the unsaturated aliphatic liquid hydrocarbons arehydrogenated to form oleflns and parans having a lower number of carbonatoms than the paraiins and olens which constituted the startinghydrocarbons which were to be treated.

The single gure is a drawing diagrammatically illustrating the apparatusused for treating hydrocarbons according to my method.

My process can be carried on in the apparatus shown either in my Patent1,752,692 or inthe apparatus disclosed in my copending applicationSerial No. 475,468 or in many known cracking convertors.

In the first step of my process I dehydrogenate the hydrocarbons bybringing the hydrocarbon to .be transformedu in a state of vaporsubstantially unmixed with reactive oxygen into contact with a mixtureof reducible metal oxides comprising preferably substantially equalparts of molybdenum oxide (M003), chromic oxide (Cr2O3) and ferric oxide(FezOa) which has been activated by approximately ten percent (10%) ofvanadium pentoxide (V205). The vanadium pentoxide can be used in amountsfalling within a range of from about 2% to about 10% by weight of thetotal weight of the three oxides; namely, chromic oxide, molybdenumtrioxide and ferrie oxide. Although the chromium, molybdenum and ferrieoxides each preferably comprise approximately 331/3% by weight of themixture, their respective proportions by weight can be varied over awide range provided the amount of oxygen necessary for dehydrogenationis liberated by the mixture. A variation of as much as 10% more or 10%less than the above proportion of any of the three oxides With acommensurate decrease or increase in the proportions of the other oxideor oxides of the mixture would work but for best results the use of thethree oxides in approximately equal amounts by weight is indicated. Amixture of any two of the chromic, ferrie and molybdenum oxides can beused if activated with vanadium pentoxide but at a loss in theefiiciency of my process.

The hydrocarbons to be transformed, if not already in the gaseous orvapor phase, are preferably vaporized by heating in a pipe still l orother suitable heating equipment, or if in the liquid phase may beinjected directly through an injector nozzle into the lower tubes 2 ofconverter 3 in which the dehydrogenation takes place.

The temperature of the reactive oxide mixture will depend on thehydrocarbon to be transformed. Preferably the reactive oxide mixturewill be maintained at a temperature falling within a range of from about800 F. to about 1100 F. The oxide mixture provides a reactive materialwhich gives up oxygen to the hydrocarbon gases and vapors passingthrough the tubes or contacted therewith and in doing so at thetemperature mentioned effects dehydrogenation thereof.

The length of time during which the reactive agent is active in theliberation of oxygen depende upon the analysis of the hydrocarbon beingtreated. By calculating the amount of oxygen present in the reactiveagent and analyzing the hydrocarbon vapors being treated, a calculationcan be made as to the period of time that the process may be operatedbefore revivifying the said reactive agent. The time is gauged on theanalysis of the material to be treated, as shown for example in thefollowing chart:

4 heated mixture of reactive materials comprising essentially inelydivided metallic iron activated with finely divided metallic copper.Preferably the mixture comprises approximately 90% of finely dividediron and of finely divided copper, but the mixture by weight can bevaried from 90 to 98% of finely divided iron and 2 to 10% of finelydivided copper. This mixture of finely Pounds oxy- Pounds per PoundsFormula Atqmic ga1. at Cubic ft. B. t. u's Jltlg oxygen grfglgd weightatmospheric per gal. per gal. degrees'F required convert; to pressureper pound aromatic Average 6. 416 1l. 66 130. 557 515 07682 492 i In allof the starting materials commonly employed in carrying out a process ofthis type, it will be found that there is a mixture of the hydrocarbonspresent and when such is the case,V

the average iigures included in the above chart may be taken for thepurpose of making such calculations. For example, if 1500 pounds of thereactive material is employed in the dehydrogenation tubes, it will befound that approximately one hundred and fifty pounds of oxygen will beliberated. After this amount of oxygen has been liberated, the reactiveagent is revivied by blowing with superheated steam for approximatelyfive minutes and then blowing with air at fifteen pounds pressure forapproximately twenty-five minutes. By reference to the above chartshowing the number of pounds of oxygen required per pound and per gallonof the hydrocarbon materials, it is possible to calcul-ate the timeperiod that the plant may be run Without revivifying the reactive agent.

The aliphatic hydrocarbons in the presence of chromic, ferric andmolybdenum oxides activated with vanadium pentoxide Vat the temperaturespecified are dehydrogenated to form aromatic hydrocarbons andunsaturated aliphatic hydrocarbons. About 80% of the hydrocarbon vaporafter dehydrogenation will be aromatic hydrocarbons (CnHzn-s) and theremaining hydrocarbon Vapors will be unsaturated aliphatic compounds.These unsaturated vapors will be, in the main, olefins. During thedehydrogenation step the olefins break down into hydrocarbons having alesser number of carbon atoms. For example, C1zHz4 splits up at thetemperatures specified into 2C6H12 which splits up into LiCal-1e, orstarting with a paraffin, CisHai is oxidized or dehydrogenated to formCisHsz which at the dehydrogenating temperatures splits up into 2C8Hisand then into 4C4Hs and finally ethylene, 8C2I-Li.

In the hydrogenation step of the approximately 20% of the vapors theentire mass of hydrocarbons to be treated, subsequent to thedehydrogenation step, are passed in the form of vapors together withsuperheated steam through the upper tubes 4 of convertor 3 in0011122.01? With a divided iron and copper is positioned in a secondgroup of tubes in which hydrogenation takes place. The temperature ofthese tubes and the nely divided iron and copper mixture should bemaintained Within a range of from about 1000 F. to about 1400 F.according to the nature of the hydrocarbons. During the hydrogenationthe temperature within the above range will vary inversely to the numberof carbon atoms present in the molecule of the material beinghydrogenated. For example, a material consisting largely of G51-Ilo willuse a temperature of about 14.00 F. whereas a material consistinglargely o'f Cial-Iss will require a lower temperature of about 1200" F.Water in the form of superheated steam is blown into the tubes duringhydrogenation and reacts with the iron and copper to liberate atomichydrogen.

During the hydrogenating step the unsaturated aliphatic liquids presentin the form of vapors are' hydrogenated to form olens and parafflns buthaving a lesser number of carbon atoms in a molecule than theparaninsand olens which formed the starting materials. The vapors from thehydrcgenating tubes may be condensed in the usual manner and treatedaccording to normal refinery practice. The gases remaining aftercondensation may be treated in conventional types of liquefactionapparatus to effect separation of the ethylene from the other gases. Theliquid condensate is a mixture of aromatic hydrocarbons and lightsaturated hydrocarbons and when tested according to the A. S. T. M.C. F.R. Motor Method it has been found to have an octane numiber of from to106 with an end point of 310 F, and a specic gravity of 30 to 35 Baum.The yield of liquid product may be varied by varying the temperature,the rate of flow, and the type of starting material. A liquid materialhaving a specific gravity of approximately 30 Baum and an octane numberin excess of 100 may :be produced in the amount of approximately tengallons to the barrel of oil, kerosene or low grade gasoline used as astarting material and also about 2800 cubic feet of gas containing 40 to45% 02H4 equal to '78 to 88 pounds C21-I4 per barrel will be produced. Aliquid product having aspecic gravity of approximately 34 Baum andhaving an octane number of from approximately 90 to 92 may be producedin anamount of approximately fteen gallons to the barrel of startingmaterial and also 2200 cubic feet of gas equal to 65 to 75 pounds CzHrper barrel will be produced. Producing 8 gallons per barrel of spirit of100 plus octane, there would be produced also 2820 cubic feet of gascontaining 85 to 95 pounds 02H4 per barrel.

From the converter 3 the vaporsl are quenched, passed through av Graytower, then through a fractionating tower (the heavy liquid beingreturned for recycling) and finally passed through a condenser wherethearomatic hydrocarbons have a specic gravity of 30-35 Baume andconsisting chiey of benzoyl, toluene and xylol are condensed out and theuncondensed gas is then passed on for further treatment.

It has been found that as the volume of liquid distillate produced isincreased, the octane value and the amount of gas is decreased. Theprocess is, therefore quite exible as to the relative amounts of liquidcondensate and gases to be produced. 'Ihe composition of the gasesvaries according to the temperature employed but in the usual instanceusing temperatures within the ranges above described, it has been foundthat the gas consists of approximately 40 to 45 percent of ethylene withvery low percentages of propylene and butylene, in the usual case notover approximately 4 to 5 percent. The balance of the produced gas ismethane.

For each barrel of starting material put through the process,approximately 2600 cubic feet of gas containing approximately 86 poundsof ethylene may be produced when approximately ten gallons to the barrelof the liquid distillate is recovered having the characteristics abovedescribed. If the liquid distillate is recovered to the extent offifteen gallons to the barrel and has the characteristics abovedescribed, the gas yield will be reduced to approximately 2200 cubicfeet of gas containing approximately seventy-four pounds of ethylene.

I claim:

1. The process of transforming hydrocarbons into other hydrocarbonsrelatively poorer in hydrogen, which consists in bringing thehydrocarbon to be transformed in a state of vapor substantially unmixedwith reactive oxygen, into contact with a mixture of molybdenum oxide,chromium oxide, and ferric oxide and vanadium pentoxide, and soregulating the temperature of the oxide mixture and vapor between about800 F. and about 1100 F. so as to oxidize a part only of the hydrogencomponent of the hydrocarbon producing thereby as reaction productshydrocarbons comprising principally aromatics and lesser quantities ofother unsaturated hydrocarbons relatively poorer in hydrogen, and steam.

2. The process as set forth in claim 1 wherein the time of contact ofthe vapor and oxide mixture is regulated so that the hydrocarbonsrelatively poor in hydrogen split up into lower boiling hydrocarbons ofthe same chemical group and thereafter contacting the vapor with amixture of finely divided metallic iron and finely divided metalliccopper in the presence of steam to hydrogenate the unsaturatedhydrocarbons produced during the dehydrogenating step.

3. The process of transforming hydrocarbons into other hydrocarbonsrelatively poorer in hydrogen, which consists in bringing thehydrocarbon'in a state of vapor into contact with a mixture ofmolybdenum oxide, chromic oxide, ferric oxide activated with vanadiumpentoxide, and regulating the temperature of the oxides and vaporbetween about 800 F. and about 11001F. and the ,time of contact of thevapor withthe oxides so as to partially dehydrogenate the hydrocarbonproducing thereby as reaction products principally aromatic hydrocarbonsand a small -amount `of oleiins having a relatively smaller number ofcarbon atoms per molecule lthan the olens produced directly from thehydrocarbon, then hydrogenating some of thek olens toproduce lowerboiling hydrocarbons .than those orig inally dehydrogenated.

4. The process as set forth in claim 3 wherein the said oxide mixturecomprises substantially by weight one-third molybdenum-oxide, one-thirdchromic oxide, 'and one-third ferric oxide, and the activating oxide,vanadium, pentoxide, comprises Iabout ten percent by weight of .themixture of the other three oxides.

`5. The process of transforming hydrocarbons into other hydrocarbonsrelatively poorer in hydrogen, principally aromatics which consists inbringing the hydrocarbon in a state of vapor into contact with a mixtureof molybdenum oxide, chromic oxide, ferrie oxide activated with vanadiumpentoxide, and regulating the temperature of the oxides and vaporbetween about 800 F. and about 1100" F. and the time of contact of thevapor with the oxides so as Ito partially dehydogenate the hydrocarbonproducing thereby as reaction products principally aromatic hydrocarbonsand a small amount of olens having a relatively smaller number of carbonatoms per molecule than the olens produced directly trom .thehydrocarbon, and then hydrogenating the `olenic part of the vapors bycontacting the same with nely divided metallic iron activated by finelydivided metallic copper in the presence of water in the form ofsuperheated steam.

6. The combination as set forth in claim 5 wherein the steam and nelydivided copper and iron are maintained at a temperature falling within arange of about 1000 F. to about 1400 F. during the hydrogenating step.

7. A process of transforming hydrocarbons selected from the groupconsisting of parains, olens, and mixtures of paraflins and olens, intohydrocarbons comprising principally aromatics and lesser quantities ofother hydrocarbons having a lesser number of carbon atoms in themolecule Ithan the hydrocarbons to be transformed,

comprising bringing the hydrocarbon to be transformed in a state ofvapor into contact with a mixture of at least Itwo metal oxides selectedfrom the group consisting of chromic oxide, molybdenum oxide and ferricoxide, activating said mix- .ture of oxides with vanadium pentoxide andmaintaining .the temperature of the oxide mixture and vapor within arange of from about 800 F. to about 1100 F. so as Ito oxidize a partonly of the hydrogen component of the hydrocarbon to be transformedproducing thereby as reaction products principally aromatics and lesserquantities of unsaturated aliphatics having a lesser number of carbonatoms in the molecule than the hydrocarbon to be transformed, and thenbringing the unsaturated aliphatics in a state of vapor into contactwith a mixture of nely divided metallic iron and finely divided metalliccopper in .the presence of superheated steam while maintaining saidcopper and iron 7 mixture and vapors at a temperature within 'a range ofabout 1000 F. to about 1400 F. to thereby hydrogenate the unsaturatedaliphatics.

8. A process of Itransforming hydrocarbons se# lected from the groupconsisting of parafns, olens, and mixtures .of parains and olens, intohydrocarbons comprising principally aromatics and lesser quantities ofother hydrocarbons having a lesser number of carbon atoms in themolecule than the hydrocarbons to be transformed, comprising bringingthe hydrocarbon .to be transformed in a state of vapor into contact witha mixture of at least two metal oxides selected from the groupconsisting of chromic oxide, molybdenum oxide and ferrie oxide,activating said mixturc of oxides with vanadium pentoxide and soregulating the temperature of the oxide mixture and vapor between about800 F. and about 1100" F. so as to oxidize a part only of .the hydrogencomponent of the hydrocarbon Ito be transformed producing thereby asreaction. products principally aromatics and lesser quantities ofunsaturated alphatics, and steam, regulating the temperature and time ofcontact of the hydrocar-J bon vapor and activated oxide mixture so that.the olens present during the dehydrogenating step split up into olenswith a lesser number of carbon atoms and hydogenating the oleiins toform paraflns having a lower boiling point than the parailins to betransformed.

9. In Ithe hydrogenating of unsaturated aliphatics, the step of bringingthe unsaturated aliphatic in a state of vapor into contact with amixture of nely divided metallic iron and nely divided metallic copperin the presence of superheated steam, the content of iron of saidmixture falling within a range ofV from about 90 to 95% by weight andthe content of copper in said mixture falling within a range of vfromabout 2 to about 10%V by Weight, and maintaining theY temperature of theiron-copper mixture and vapor within a range of from about 1000 F. toabout 1400 F. whereby said unsaturated -aliphatics are hydrogenated.

ALEXANDER S. RAMAGE.

